How to build a Concrete Patio
Forming in concrete is probably the easiest way to build a patio. You can dye concrete to any color you require or you can tile it if you wish. It can also be stamped to create a pattern.
Dig out 8" deep and approx. 1 foot wider on all sides than your proposed patio size. Fill the hole with crushed stone about 6" deep and then compress with a vibrating plate available from all tool hire shops. Your foundation should be 4" deep so keep adding stone until the required depth is reached.
Form a box on top of your foundation with some 4" X 2" lengths of timber to the size of your proposed patio. If your patio is butting up to your home then you will only need 3 lengths of timber.
Using a tape measure, check your timber form is square by measuring corner to corner. Both measurements should be identical.
Once square, use a level and adjust accordingly. If you are butting up to your home you will need to make sure your patio has a slight slope away from the building, 1" for every 6ft is enough or a moderate climate.
Now secure your timber form in place by knocking in stakes or steel bars around the outsides. One every yard should be enough. They will need to be level or just below the top of the timber for when you do the screeding. Check the levels again to make sure nothing has moved and once you are happy you are ready for the concrete.
Mix the concrete at a ratio of 1 cement, 2 sand and 6 aggregate (gravel). If you are using premix bags of aggregate then it is 6 shovels to 1 cement. Do not over water. When it is tipped from the mixer into the barrow it should form a mound and not level off.
You will need a hand to lift the barrow over your timber form to ensure it doesn't move. If you are working alone build a ramp with some timber but rest it on brick or block and not on the form.
A good barrow full (2 cement, 4 sand and 12 gravel) should cover approx. 4 square feet. If you are butting up to your home start up against it and work backwards.
Screeding - You will need a hand with this. Get a length of timber that is long enough to span the width of your patio. With you on one side and a mate on the other, use a sawing motion to drag back the access concrete. You will spot any low spots straight away. Fill any with more concrete and screed again. Once finished, repeat.
Now go back to the top with your timber and "tap" the concrete by both raising the straight edge about 4" and tapping it back down. It takes a few minutes for you and your mate to do this in synchronisation.
Keep tapping while you work your way back down the length of the patio. This will vibrate the concrete and get rid of tiny air pockets that could weaken it.
Finishing - If you plan to tile your concrete patio simply drag an upside down yard brush over it from one side to the other working your way up. These lines will give a good fix when the tiles are laid.
If you aren't putting anything on it use a wooden float to finish. Use a circular movement working over small areas at a time.
Also in this section